Chamber oven for coal distillation



Jan. 16, 1934. c. STILL CHAMBER OVEN FOR COAL DISTILLATION Filed Jan. 9. 1931 2 Sheets-Sheet l Jan. 16, 1934. Q STILL CHAMBER OVEN FOR COAL DISTILLATION Filed Jan. 9, 1951 2 Sheets-Sheet 2 I ERA Jnrenfor ZW/ 597/ Patented Jan. 16, 1934 UNITED STATES PATENT OFFICE Application January 9, 1931, Serial No. 507,678, I

and in Germany January 14, 1930 2 Claims.

The invention consists in improvements in the means for drawing ofi by suction the volatile products of distillation from the interior of the charge of coal in chamber ovens for the dis- 6; tillation of coal, more particularly those for producing coke and gas.

The drawings, which represent a vertical longitudinal section through the center of a coking oven chamber, illustrate the preferred embodi- 101 nent of the invention. Figure 1 shows the right end of an oven chamber in vertical longitudinal section, while Figure 1 is a continuation thereof, showing the left end of the chamber, likewise in vertical longitudinal section.

The oven chamber, which is defined below by the sole 1, above by the arched roof 2, and laterally by two heating walls parallel to the plane of the drawings, and at its ends is closed by doors 3, has in the roof 4 the usual openings 5 for introducing the charge of coal and a gas discharge opening or outlet 6 which is connected by an ascension pipe '7 with the usual gas and tar main 8. The framework supporting the hydraulic main 8 carries a separate gas collecting main 9 extending over the whole length of the battery. The oven chamber is charged with the coal 10 to be coked, so that as usual there is a free space 20 for collecting the gas above the surface 11 of the coal.

' Iron boxes 12, about 6 to 10 in number, distributed uniformly over the length of the chamber, are provided in the roof 4 between the openings 5 and 6. The boxes have covers 13 which are gas-tightly closed by water seals. Each of the boxes 12 is connected by a lateral pipe 14 with a common gas collecting pipe 15 arranged in the roof 4 parallel to the longitudinal axis of the oven and connected by an elbow joint 16 with the main 9. A discharge pipe 1'7 near the elbow joint 16 serves for drawing off condensates carried over into the pipe 15.

In the bottom of each box 12 there is a tubular member 18, projecting upwards into the interior of the box, and a tubular member 19 of the same diameter projecting downwards. The members 18 and 19 each serve to guide and hold in position within them a concentric tube 21 which is extended sufiiciently far downwards to traverse not only the free gas collecting space 20, but to project also through a further distance of about 300 mm. below the surface 11 of the coal charge 10. At its upper end, which projects into the box 12, the tube 21 carries a bell 22, the feet 26 of which rest on the bottom of the box. The

.65. bell 22 forms, with the casing of the box 12 and the inner tube 18, a water seal by which the inside of the tube 21 is sealed from the outside.

In the prolongation of each tube 21 and coaxial with it, a tubular passage or duct 23 is provided within the body of the charge 10 of coal.

These ducts 23 which are only formed by the mass of coal itself and the tubes 21 form a channel for drawing off by suction the volatile products of distillation from the interior of the charge of coal. The gases and vapors drawn off pass into the box 12 which is closed on all sides, through the pipe 14 into the pipe 15, and then through the elbow joint 16 into the gas collecting main 9 common to the whole battery.

According to the invention the ducts 23 in the coal are constructed so as to form an efiicient gas-tight connection at 21 (Figure 1 with the tubes 21, that is, so that sufficient gas pressure differences, i. e. of values such as to be obtained in the operation of the oven, can be maintained '75 between the free gas space 20 above the coal charge 10 and the ducts 23 within the latter.

Practically, in the space 20, that is in the free interior of the oven chamber, the gaseous pressure must approximate very closely to, that is must differ at most by a few mm. of the water gauge from, the external atmospheric pressure, since the unavoidable leakage at the oven brickwork makes impossible the maintaining of large differences of pressure.

On the other hand, it is found in practice that in order to lead away by suction the volatile products of distillation effectively from the interior of the coal charge, the pressure in the interior of the coal must be maintained at an amount of at least 50 mm. and even much more of the water gauge below atmospheric; this is due mainly to the high resistance which the gases and vapors to be drawn ofi meet in their path through the tightly packed particles of coal. It is clear from this consideration, that the ducts 23, extending to the surface 11 of the coal, would be practically ineffective, if the tubes 21 would not ensure sufficient gas-tight closure between these ducts 23 and the free space 20 when there is a pressure difference of the order stated.

In order to form such gas-tight discharge paths according to the invention the following process is adopted:

After the residue of the coke has been discharged from a chamber in which coking has been completed and all the tubes 21 have been removed, the coal 10 is charged into the chamber in the usual manner and the coal surface 3 11 is levelled. Then, as shown in the box 12 of the drawing, a cylindrical iron rod 24 of about 50 mm. diameter or more, pointed at the bottom and fastened by a chain 25 to a pulley block, is inserted from above through the guiding tubes 18 and 19 andpushed downwards into the coal charge 10. In this way a vertical duct 23 extending to the upper surface of the coal is formed, as shown in connection with the the box 12 on the right side of Fig. 1 of the drawings.

The rod 24 is either immediately withdrawn upwards by the chain 25, if the coal 10 is sufficiently coherent to ensure the durability of the duct formed by this means, or, if the condi tions do not allow this, the rod is left in the coal 10 until, after the process of distillation has commenced, the duct is sufiiciently consolidated. After the rod 24 has been removed, the tube 21 is inserted from above. If the external diameter of the tube 21 is somewhat greater than the diameter of the coal duct produced by the rod 24 and if, preferably, also the lower end of the tube 21 is provided with a conical taper, the tube is jammed so tightly in the duct 23, that the connection made is sufiiciently gas-tight for the purpose of the invention. When the tubes 21 are telescopically inserted into the ducts 23, the tight connection above referred to is formed with the charge at 21 from the top of the charge downwards for some distance. In addition to the seal formed by virtue of the external diameter of the tubes 21 being somewhat greater than the diameter of the ducts 23, the seal is made more effectively gas-tight by the charge adhering to the tubes as the coking of the charge proceeds.

Other methods of forming the discharge passages are possible, which also come within the scope of the invention. For example, the previously described method can be modified in the following manner: The tubes 21, after the coal 10 has been charged and levelled, are inserted in the tubular members 18 and 19 and their lower ends driven below the surface 11 of the coal 10. The iron rods 24 are then pushed through the tubes 21 into the coal 10. Obviously, this method also ensures a gas-tight connection according to the invention.

The process can also be employed when working with chamber ovens charged with rammed or pressed coal cake. In this case it is advantageous to form the ducts to be provided in the interior of the body of the coal before charging, while the cake is still outside the oven chamber, or directly after the cake has been made. After the coal cake has been inserted in the oven chamber, the tubes 21 are inserted from the oven roof, as described with reference to the example illustrated, so that the lower ends of the tubes communicate with the ducts formed.

When the charge 10 has been completely coked, or eventually, some time before, the tubes 21 are drawn upwards and removed. The coke body can then be discharged without hindrance in the usual manner from the oven chamber.

In the example illustrated in the drawings it is assumed, that, besides the volatile products of distillation which are drawn off by suction through the passages 23 and tube 21 from the interior of the body of the coal, certain gaseous products of distillation are also led away from the outer parts through the gas collecting space 20, the opening 6 in the roof and the ascension pipe 7 into the usual hydraulic main 8.

However, the advantages due to the invention apply also to the same extent if the suction is only exerted on the interior of the body of coal, but not at the same time on the outer'parts of the coal charge, since, even if the last-mentioned suction action is entirely omitted, nevertheless the condition always exists and is to be maintained that the gaseous pressure prevailing at the roof and walls of the chamber, i. e. at the outside of the coal charge, is practically equal to the atmospheric pressure and always much higher than the suction pressure applied to the interior of the charge of coal. There is always, consequently, a difference of gas pressure against which the connection according to the invention must besealed. For this reason, it is also unimportant whether the oven chamber is filled so far with the charge of coal that there 'is no actual gas collecting space; for in that case also gaseous pressures substantially equal to atmospheric are present along the arch of the chamber and the chamber sides of the heating walls,

that is, along the outer surfaces of the body of coal, in the unavoidable gaps between the coal and the chamber itself. Such full charges of coal can occur with ovens having inclined, or vertical chambers.

From this it follows that the invention can be applied to chamber ovens of any kind, therefore to those with horizontal, inclined or vertical chambers.

What I claim is:

1. In apparatus of the class described, the combination with a chamber oven including a roof having apertures, said oven being adapted to contain a charge of coal and having a space between said charge and the roof, means operating through the apertures in said roof for forming ducts in the interior of the charge, discharge tubes extending into the charge and sealed within the charge in the upper end of said ducts, means within the roof for sealing said tubes against the space between the charge and the roof, and a horizontal gas collecting pipe connected with the upper end of said tubes.

,2. In a chamber oven adapted to contain a charge of coal and having a free gas collecting space between the top of the charge and the oven roof, the combination including a roof having apertures, means operating through the apertures in said roof for forming ducts in the in terior of the coal charge, discharge tubes extending into the charge sealed within the charge in the upper ends of said ducts, means within the roof for sealing said tubes against the space between said charge and said roof, a horizontal gas collecting pipe connected with the upper end of said tubes, and a gas discharge outlet in said roof for said gas collecting space communicating with a tar main outside the oven chamber.

CARL STILL. 

